A year ago, we were told we had 12 months to make poverty history. So, in the bleary cold light of the new year, how does our achievement stack up? Did a year of unprecedented focus on Africa - rock concerts, 250,000 demonstrating in Edinburgh and an extraordinary degree of political engagement at the highest levels - succeed?

In recent weeks there has been no shortage of aid agencies and government advisers attempting to draw up the balance sheet. The year ended on a gloomy note. The failure in Hong Kong to achieve anything like a positive outcome for developing countries was a big blow, given that the huge costs of unfair trade dwarf the pocket-money deals on debt and aid. Even more depressing was the news from Africa. It was not just the string of crises - from Malawi and Zambia in famine-struck southern Africa to the fragility of the peace in Sudan and the ongoing conflict in Darfur - but, more worryingly, the much-favoured reform-minded governments of key countries such as Uganda and Ethiopia showed an ugly ruthlessness.

So the campaign fizzled out. It lost momentum in the public imagination after the London bombings in July. The politicians may have ploughed on at the UN summit in New York in September, but they no longer did so under the glare of media attention.

But if you stand back from the past few months and assess the whole year, something more optimistic becomes clear: the politics of global inequality has come of age. It has become part of the mainstream in this country, in a way that was unthinkable a decade ago. In the past, third-world poverty did occasionally grab attention, but only when framed as an appeal to respond to a humanitarian crisis. This year marked a step change in the popular understanding that global poverty is about more than dipping your hand in your pocket for the odd pound coin. The involvement of celebrities ensured slots on primetime TV and the attention of newspapers like the Sun, and reached an entirely new constituency. Issues such as trade justice, once regarded as the obscure obsessions of the hairy, the sandalled and the tattooed, are percolating through to your average supermarket shopper.

At the same time as the shift at a popular level gathered pace, 2005 saw the deepening of a cosy relationship between government and the aid agencies. In the 1990s, the debt campaigners laboured away on the margins of the Labour party, and never dreamed of the kind of easy access to ministerial ears their successors regard as routine. Government and aid agencies are now tied into a symbiotic - and not unproblematic - relationship as they bolster each other's credibility. During much of 2005 they were working hand-in-glove (the agencies' criticisms post-Gleneagles were a short-lived bid to scramble back some vestige of independence). They both have much at stake - to show that campaigning can work and politicians can make a difference.

The final confirmation of this mainstreaming came when David Cameron picked development as one of his six key themes on becoming leader of the Conservative party, even if he did forget to deliver that bit of his memorised speech. The point is that in British politics, having something to say about global poverty is now regarded as an essential to get the tone of your political pitch right. It hits two Cs: compassionate and contemporary.

So if the politics of global inequality has come of age, what are its ingredients? At a political level, the rhetoric is grandiose. Any aspiring world statesman now has to deliver speeches on child mortality and talk about female literacy rates in the developing world as if they a) knew what they were on about and b) spent the early hours worrying about it. There's a new expectation of government. That's a step change from the era of Reagan and Thatcher.

At street level, there's a vague sentimentality, a bit of emotional manipulation, a fair dollop of the consumer feel-good factor (the "I want to feel virtuous and consume"). It's not political mobilisation or activism in any traditional sense, but it's enough to motivate someone to buy the white wristband and email Tony Blair. It's the celebrity factor that delivers this constituency - and that makes the likes of Bono, Geldof and the film-maker Richard Curtis into a new breed of political actor. Love 'em or loathe 'em.

The big worry is that this kind of politics has no kind of sustainability. It's a flash moment, and short attention spans ensure the media has moved on to something else before the politicians' rhetoric has been translated into delivery. This is particularly pertinent to the Gleneagles aid deal, which could very uneasily come unstuck, given the huge increases in aid required from reluctant countries such as Germany and Italy - of 106% and 276% respectively by 2010.

But perhaps an even bigger worry is that the politics of global inequality is characterised by a wishful naivety. Tony Blair's Commission for Africa in March last year posited its analysis of a turnaround in Africa on the existence of a new generation of African governments. From the start, some argued there was no such thing, and their voices have only grown louder in the summer, as the Ethiopian government, whose president was a member of the commission, shot dozens of demonstrators and detained thousands. More recently, criticism of Uganda's Yoweri Museveni has come to a head over the imprisonment of an opposition leader. A batch of books this year, including Matthew Lockwood's stinging analysis The State They're In and Martin Meredith's history of the past 50 years in Africa, point to the fact that most African governments have a poor, often abysmal, record of delivering development, and there's little reason to believe that has changed.

So there is fat chance that 2005 made poverty history. It finally offered a decent debt deal after 20 years of campaigning; there was a promise, yet to be fulfilled, to double aid by 2010; and there was a surprise goody thrown in - a hugely ambitious target for universal access to HIV/Aids treatment. In terms of G8 summits, it was a big deal; in terms of a breakthrough for Africa, forget it. Aids and climate change will ensure that the suffering of millions of Africans will plague our consciences for decades to come.

But for all its shortcomings, the coming-of-age of the politics of global inequality is being driven by an important issue that will ensure it stays on the international agenda: at its heart is a question of legitimacy. The west's global dominance is being challenged as unjust - whether that is by the World Trade Organisation's new bloc of leading developing countries or even by the fanatical violence of the Islamist extremists. The huge wealth generated by globalisation, with its equally huge ecological footprint, cannot largely be for the benefit of a tiny proportion of the world's population.

Increasingly we question our own legitimacy, as well as being called to account by others. 2005 spurred a new expectation across the developed world from the new campaigns in Japan to the US that politicians have to show they do more than just talk about it. That's no small achievement.